The purpose of this research is (1) to develop and standardize methods for in vitro activation of promutagens by green plants; (2) to characterize plant activation and compare it with mammalian microsomal activation; (3) to incorporate in vitro plant activation products with microbial assays for mutagenicity; and (4) to compare the genetic activities of the promutagens assayed in objective three with an in vivo forward mutation assay in the angiosperm Zea mays. We originally developed the concept that plants could activate chemical promutagens into mutagens and suggested an environmental hazard may be present with respect to modern agricultural practices. In this research we shall specifically investigate if maize tissue preparations can activate known chemical promutagens into mutagens. The genetic endpoints we will use include primary DNA damage rec assays in Salmonella typhimurium and Bacillus subtilus, reverse mutation assays in S. typhimurium, and reversion at the waxy locus in maize microgametophytes. Using both green and etiolated seedlings this research would determine whether plant activated mutagens require photosynthetic processes, and by utilizing several genetic endpoints determine whether such agents can induce a spectrum of genetic events. We propose to define a routine methodology for in vitro plant activation, one which will prove a complement to the mammalian microsome assay presently used in a variety of laboratories. Considering the wide variety and large amounts of chemicals released into the environment, the information that would be generated by this proposed research will be useful in developing policies for the protection of the public health.